1. Field of the Invention
The invention relates to solid centric stop mechanisms or apparatus which are used in locating solid centric location with a dental model system which includes a flexible articulation means. The present invention provides improved centric stop means for dental model systems that are similar to those disclosed in U.S. Pat. No. 5,846,076 and PCT Pub. No. US 2003/0207230 A1. The present invention discloses additional, new centric stop apparatus that is to be used with the dental models and articulation means that are disclosed in U.S. Pat. No. 5,846,076 and PCT Pub. No. US 2003/0207230 A1, and the complete disclosures in those publications are included herein by reference.
2. State of the Art Prior to the Invention
The present invention provides an improved centric stop mechanism that is used in locating solid centric location when a dental model is being used that incorporates flexible articulation members. As disclosed in U.S. Pat. No. 5,846,076 and PCT application No. PCT/US01/05683, the dental model can consist of two base stones that are cast from dental casting material. One leg of an articulation member is either encapsulated within the casting material (as in U.S. Pat. No. 5,846,076) as each of the base stones are being cast, or a base stone is cast on a tray that has a leg of an articulation member either formed integrally with the tray or firmly attached and connected to the tray. In either case, the leg of the articulation member projects from respective base stone, with the leg of the articulation member having a free end that extends from the respective base stone. The free end of the leg of one articulation member extending from one base stone is adapted to be pivotally connected to the free end of the leg of a complimentary articulation member extending from a complimentary base stone to form a dental model, wherein the two base stones of the dental model are restrained by the articulation member so that the two base stones can be pivoted about the pivot axis of the pivotal connection connecting the complimentary legs of the articulation members to replicate biting action between the upper teeth and lower teeth of the dental model. This procedure is well known now in the art and is explained in detail in my U.S. Pat. No. 5,846,076.
Inasmuch as the legs of the articulation member are elongate and relatively thin, they have at least some flexibility. The flexibility is advantageous when the technician desires to move the parts of the dental model in a grinding type motion to check proper alignment of the dental model during such a grinding motion. This grinding type motion is produced by moving the complimentary base stones so as to flex the legs of the articulation member to allow the base stones to move back and forth in a lateral grinding motion relative to each other.
However, when the technician attempts to bring the base stones together to establish proper centric occlusal positioning, any flexing of the legs of the articulation member that allows undesirable up and down movement of the base stones relative to each other due to such flexing of the legs as opposed to the pivotal movement of the respective pair of pivotally connected legs is highly undesirable. In particular, when teeth are being restored at the posterior end of the dental model and no occluded opposing teeth are present to create a natural stop, it becomes necessary to artificially create a vertical stop in order to prevent the over closure of the opposing model. Thus, the technician is able to create accurate solid vertical relationship of the opposing dentition that is being restored with a crown or bridge.
In recognizing the need for a vertical stop, artisans in the past have used the following ways to achieve such a stop. In one method, a vertical rod or shore is glued to the model or articulation frame or model base, with the rod being cut at the required length to prevent over closure of the opposing models. In a second method, a mound of model stone is placed at the area needed to stop over closure against opposing models. In a third method, a cast in place post is immersed into the wet model stone of the second cast model positioned against the opposing model at the required height to set the vertical stop position. All these previous methods are cumbersome and require extra time spent by the technician. These methods also frequently require readjustment procedures and are difficult to adjust or fine tune the final vertical elevation of the cast models.
3. Objectives of the Invention
It is a broad object of the present invention to provide a solid centric stop mechanism that prevents the base stones of a dental model from being moved to an improper position that might otherwise be allowed by improper up and down type flexing of the legs of the associated articulation member.
A principal object of the present invention is to provide a solid centric stop mechanism that is either removably attached to the base stone of the dental model or removably attached to a leg of an articulation member that is in turn firmly attached to or encased in the base stone of the dental model.
An equally important object of the present invention is to provide a centric stop mechanism that is removably attached to the dental model, with the stop mechanism being further provided with means for adjusting or fine tuning the final vertical positioning of the upper and lower base stones of the dental model.